Ipilimumab and Nivolumab in Leptomeningeal Metastases

Inclusion Criteria: * Participants must have histologically or cytologically confirmed disease from any solid tumor * Age ≥18 years. * Eastern Cooperative Oncology Group (ECOG) performance status ≤2 (Karnofsky ≥60%) * Life expectancy of greater than 3 weeks * Participants must have normal organ and marrow function as defined below, all screening labs should be performed within 10 days of treatment initiation. Adequate Organ Function Laboratory Values: Unit key: mcL = microliter, ULN = upper limit normal * Hematological * Absolute neutrophil count (ANC) ≥1500 /mcL * Platelets ≥100,000 / mcL * Hemoglobin ≥9 g/dL or ≥5.6 mmol/L without transfusion or Erythropoietin (EPO) dependency (within 7 days of assessment) * Renal * Serum creatinine OR Measured or calculated creatinine clearance (GFR can also be used in place of creatinine or CrCl) ≤ Serum creatinine ≤ 1.5 x ULN or creatinine clearance (CrCl) ≥ 40 mL/min (if using the Cockcroft-Gault formula below): * Female CrCl = (140 - age in years) x weight in kg x 0.85 72 x serum creatinine in mg/dL * Male CrCl = (140 - age in years) x weight in kg x 1.00 72 x serum creatinine in mg/dL * Hepatic * Serum total bilirubin ≤ 1.5 X ULN OR Direct bilirubin ≤ ULN for subjects with total bilirubin levels \> 1.5 ULN * Aspartate transaminase (AST) and Alanine transaminase (ALT) ≤ 3 ULN OR ≤ 5 X ULN for subjects with liver metastases * Albumin ≥ 2.5 mg/dL * Coagulation * International Normalized Ratio (INR) or Prothrombi…